The reason this works locally is because you're using the file:// scheme on your local machine (or http:// if you have a local development server). The browser doesn't have a problem loading an external script over HTTP in this case.

However, Github Pages is hosting your file over HTTPS (a secure connection) for you. For security reasons, the browser won't load a script over HTTP if the page is hosted on HTTPS.

Just change the code in your <head> tag to load the script over HTTPS:

<script src="https://code.jquery.com/jquery-1.10.1.min.js"></script>

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